[Availability of mammographs in Mexico: Is it possible to expand coverage]. / Disponibilidad de mastógrafos en México: ¿Es posible ampliar la cobertura?

Background: Breast cancer screening coverage in Mexico is limited. It is necessary to configure the Mexican health system to make it capable of producing more mammograms, without neglecting quality and diagnostic opportunity. Objective: To project the coverage of breast cancer screening programs according to the mammographs availability in the Mexican Health System. Material and methods: An exploratory study was conducted correlating the number mammographs available in the Mexican Health System with women between 40 and 69 who are the target of screening programs in Mexico. The analysis consisted of calculating the coverage of breast cancer screening programs if each mammograph could perform 6336 screening mammograms per year. All the calculations were made with the information of the year 2020 as the most current data in terms of population density. Results: It was determined that the number of mammographs is enough to raise the offer of screening studies to ≈50% at the national level. There are even states whose coverage capacity is projected above 70%. Some of them are Mexico City, Colima, Durango, Quintana Roo, Zacatecas, Baja California Sur and Coahuila. Also, it was observed that the distribution of mammographs is not equitable in the national territory, suggesting investment both in equipment and in screening strategies for breast cancer. Conclusions: Our data show that it is possible to advance in preventing breast cancer in Mexico, although the improvement of the management capacities of the Mexican Health System is required to improve both the coverage and quality of the breast cancer screening programs.

Introducción: la cobertura de detección de cáncer de mama en México es limitada. Es necesario configurar al sistema de salud mexicano para hacerlo capaz de producir más mastografías, sin dejar de lado la calidad y la oportunidad diagnóstica. Objetivo: proyectar la capacidad de cobertura de los programas de detección oportuna de cáncer de mama en México en función de los mastógrafos disponibles en las instituciones públicas del país. Material y métodos: se hizo un estudio exploratorio correlacionando la cantidad de mastógrafos del sector público con las mujeres entre 40 y 69 años quienes son el objetivo de los programas de tamizaje en México. El análisis consistió en calcular la población blanco-cubierta, a nivel nacional y por estado, asumiendo que cada mastógrafo pudiera ejecutar 6336 estudios de tamizaje al año. Todos los cálculos se realizaron con la información del año 2020 por ser los datos más actuales en materia de densidad poblacional. Resultados: se determinó que se cuenta con el número de mastógrafos suficiente como para elevar la oferta de estudios de tamizaje al 50% a nivel nacional. Incluso hay estados cuya capacidad de cobertura se proyecta por arriba del 70%. Algunos de ellos son Ciudad de México, Colima, Durango, Quintana Roo, Zacatecas, Baja California Sur y Coahuila. También se observó que la distribución de estos equipos no es equitativa, habiendo estados con grandes necesidades de inversión en equipo y, por ende, en estrategias de tamización para cáncer de mama. Conclusiones: nuestros datos demuestran que es posible incrementar la cobertura de los programas de detección oportuna de cáncer de mama en México, aunque es necesario mejorar las capacidades gerenciales de nuestros programas para que estos impacten en la cobertura, pero también en la calidad.

PSF, LSF and S/P in mammography: GEANT4 validation.

The main goal of this study was to validate the predictions of GEANT4, a Monte Carlo code originally developed for high-energy physics, for low-energy (10-40 keV) photon transmission and scattering through matter similar to biological tissue. We compared GEANT4 calculations with existing phantom data relevant for the mammographic imaging technique. This work showed that scattered-to-primary ratio data can be simulated using GEANT4 with a deviation smaller than 5%. At the same time, we encountered a limitation in the small-angle region description by the code, which is important for point- and line-spread function calculations. The comparison with forward angle data showed that the GEANT4 models, known as "G4 Low Energy" and "G4 Penelope", describe the measurements for X-ray beams typically used in mammography better than 10% for angles above 10 degrees, and that "G4 Low Energy" is preferable to "G4 Penelope ". The results confirm the possible use of GEANT4 for the optimization of applications based on low-energy photon transmission and scattering.

Evaluation of equipment performance, patient dose, imaging quality, and diagnostic coincidence in five Mexico City mammography services.

BACKGROUND: Regulations concerning the use of x-rays in medical diagnoses were published in Mexico in 1997. In this work, we evaluate technical aspects of mammography services in the Mexico City area and radiation dose and coincidence between the radiological interpretation by the institution radiologist and by a panel of experts. METHODS: Following methodology proposed by the American College of Radiology and the European Community among others, we have evaluated the performance of six mammography systems in Mexico City public and private services. The studied services carry out approximately one half of the mammography studies in the capital's metropolitan area. RESULTS: The systems comply with 53-82% of a total of 31 applied quality control tests and measurements, which include the mammography unit, x-ray generation, collimation, automatic exposure control, compression devices, grid and image receptor, film processing, darkroom, viewboxes, dose, film rejection, and image quality. The elements that most frequently fail are film processing, darkroom, and light boxes; average ACR phantom score is 11.2 (9.5, 12.0); mean average glandular dose measured with the phantom is 1.00 (0.71-1.15) mGy, and measured in patients is 1.75 (0.3, 4.9) mGy; coincidence between radiologic reports (BI-RADS) by the institution radiologist and a panel of experts is obtained in 35% of studied cases. CONCLUSIONS: Statistical analysis of results indicated that the level of equipment performance is correlated with image quality, image quality estimated by the panel of radiologists is correlated with phantom score, and coincidence in clinical mammography reports is not correlated with equipment performance and appears to depend on the radiologist's experience.